This invention relates to roof systems, and more particularly to sheet panel roof systems of the standing seam type.
Panels of substantially rigid sheet material, such as roll-formed sheet metal (e.g. aluminum or steel) panels, are widely used for roofing, either to provide a protective outer cladding for a continuous roof substructure of wood or the like, or in themselves to constitute a roof when mounted directly on a support structure of spaced beams. In many instances, it is preferred to employ a so-called standing seam roof system, comprising a plurality of elongated, channel-shaped sheet panels each having a central web and first and second longitudinal flanges respectively projecting upwardly (e.g. as much as two or more inches) from the web along opposite sides of the panel, the flanges being commonly formed with one or more inward and/or outward bends. These panels are disposed on a supporting roof structure in side-by-side parallel array, the roof structure typically having at least a slight pitch and the panels being oriented with their long dimensions perpendicular to the ridge of the roof; the first longitudinal flange of each panel lies closely adjacent the second longitudinal flange of the next panel to constitute therewith a standing seam, so that there is a standing seam at each junction between adjacent parallel panels in the array. A plurality of clips, fixedly secured to the supporting roof structure at spaced locations along each standing seam are interposed between (and engage) the adjacent panel flanges constituting that seam to anchor the panels to the roof structure. For protection against penetration by moisture, each standing seam may be covered by an elongated cap member mounted thereon, or the flanges constituting the seam may be nestingly interfitted with each other; in addition, caulking or sealant material may be provided along the seam.
It is to be understood that the terms "inwardly" and "outwardly" (or "inward" and "outward") as used herein refer, respectively, to directions toward and away from the plane longitudinally bisecting and perpendicular to the central web of a panel, while terms such as "upper," "upward," "above," "lower," "downward," and "below" refer to vertical directions obtaining when the panel is mounted in its intended or customary orientation on a roof.
A standing seam roof system as described above affords significant advantages in comparison to other types of sheet panel roof systems. In particular, the panels of a standing seam system are not penetrated by screws or other fasteners except at the eave and ridge of the roof (and at overlapping ends of panels in cases where the eave-to-roof distance is greater than the length of one panel), and the panels are free to expand and contract (with change of temperature) to a significantly greater extent than if they were fixedly fastened by nails or screws along their lengths. The problem of undesired entry of water to a building through fastener holes in roof panels is thereby greatly reduced, as is the related problem of fastener hole enlargement (and consequently increased admission of water) incident to panel expansion and contraction. The channel-shaped panels also act as wide, deep rain-carrying troughs, enabling use of the panels on roofs of very slight pitch without resort to costly expedients for preventing leaks.
Various difficulties, however, have been presented by standing seam roof systems heretofore known or proposed. In many of such systems, closure of the standing seams requires deformation of the cap member or interfitted panel flanges with a special, powered crimping or seaming machine at the installation site; the provision and operation of this machine is undesirably costly, inconvenient, and time-consuming for the installer. Other standing seam systems present disadvantageous complexity in fabrication or installation, because of the number or intricacy of their components and/or because of the high precision required for proper assembly. In some systems, the seams are sealed at locations likely to be immersed (and thus vulnerable to leakage) in heavy rains; or the seams have an aesthetically undesirable asymmetrical appearance. Moreover, known types of anchoring clips, though holding the panels on the roof structure, commonly do not support the panels, and therefore the panels can be installed with such clips only on types of roof structures that themselves provide direct support for the panels.